IXTKRRELATIOXS OF GKNKRA. xlix 



a rule witli small, often more or less concealed, neck- tufts), and the 

 general size moderate. 



The genus has divided into three branches (subgenera), Ronsetlu.', 

 Sfenoiujclcris, and Lissom/cteris. The subgenus Eovsdhis (ten 

 species) ranges over the Ethiopian and Oriental regions (extending 

 from the former northward to Egypt, Palestine, and Cyprus) and 

 the whole of the Austro-Malayan subregion, while SUnonycteris 

 and Lissonjfcferis are confined to tropical Africa. In Stenonycteris 

 (two species) the cheek-toeth are become narrow, m^ is reduced in 

 size, and the facial axis more strongly deflected than in Eousettus 

 s. str. Lissotij/cieris is somewhat more aberrant : the brain-case 

 is peculiarly flattened posteriorly and the facial axis even less 

 deflected than in Eousettvs, hoth characters giving the skull, viewed 

 in profile, a rather striking resemblance to that of Epomops ; the 

 prema.xillfe arc ankylosed together anteriorly, the postdental palate 

 rejatively longer, the cheek-teeth shorter and broader (subsquarish) 

 with the ridges more cusp-like (shorter antoro-posteriorly and 

 higher vertically), those of p, separated, m' and p, reduced in 

 size. 



Eidolon (three species, Ethiopian and jralagasy regions) has 

 originated from a HouseUits-hke bat. p' is not quite so much 

 reduced as in Roitseftus, but in other respects Eidolon is a little 

 more peculiar : the premaxill?c are spaced in front, the postdental 

 palate more expanded laterally, the tympanic bone elongated to 

 form a short bony auditory meatus (a character unique among 

 Bats),_ m, longer (antero-posteriorly) than usual, the sexual differ- 

 entiation rather more pronounced (males always with neck-tufts, 

 females often conspicuously paler than males), and the general size 

 of the animals larger. 



Boneia (one species, Celebes) is closely related to liouKettu.t, 

 but more specialized. The lower canines are slanted strongly 

 outward, this necessitating a greater breadth of the palate between 

 the upper canines, this again making the rostrum conspicuously 

 broader in front; perhaps as a further consequence the premaxiila; 

 are spaced anteriorly ; but in all other respects the skull is 

 psscntinlly Rousettine in sha]ie. i' has disappeared, i^ is somewhat 

 increased in size, the molariform teeth flatter, the outer and inner 

 cusps of Pj separated and those of p' and p^ less completely fused 

 than in liovseftus. The external characters are practically un- 

 modified. 



Pteropus, the largest genus of Megachiroptera (eighty-five 

 species, a hundred and three forms) and one of the most widely 

 distributed, has originated from a bat essentially similar to 

 Rousettus, but slightly more primitive than the living species of 

 that genus, in so far as it must have had a narrower palate, the 

 tympanic ring thinner, and the cusps of p^ and p^ distinctly 

 separated. The dentition is in all typical sjiecies of the genus 

 considerably heavier than in liovseifus, hence the skull much more 

 heavily built, the crests stronger, the postorbital processes lono^er, 



d 



